Taking advantage of aquifer heterogeneity in designing construction dewatering systems with partially penetrating rechar
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Taking advantage of aquifer heterogeneity in designing construction dewatering systems with partially penetrating recharge wells J. H. van Lopik 1,2 & N. Hartog 1,2 & R. J. Schotting 1 Received: 6 December 2019 / Accepted: 10 August 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract During construction dewatering, artificial recharge with wells might be required to discharge the pumped groundwater. On the one hand, artificial recharge wells must be placed as close as possible to the construction site to limit the above-ground space for the dewatering infrastructure and the transport costs, while on the other hand, the distance from the dewatering site must be considerably large to reduce the hydraulic impact and minimize overall pumping costs. Commonly, artificial recharge wells are completed with filter screens that penetrate large portions of the aquifer. The present study investigates the efficiency and potential of artificial recharge with partially penetrating wells (PPWs; filter length of 1 m) in heterogeneous aquifers. This was done by conducting scenario modeling of simple dewatering schemes with one abstraction well and one artificial recharge well, as well as with experimental field tests. In these field tests, artificial recharge on a fully penetrating well (FPW), as well as on a PPW screened at a layer of relatively high permeability (300 m/day), is explored. The present study shows that the use of recharge PPWs screened at depth in high-permeability layers of the aquifer minimize the hydraulic impact at the dewatering site. Scenario modeling shows that recharge PPWs can be installed much closer to the dewatering site than FPWs. Assessment of the optimal screen depth of the PPW, as well as the mutual distance between the wells, requires a proper consideration of the vertical variability in the hydraulic conductivity of the aquifer. Keywords Construction dewatering . Artificial recharge . Heterogeneity . Injection wells . Partially penetrating wells
Introduction In the last few decades, the use of underground space in urban areas has drastically increased for the construction of building foundations and infrastructure (e.g. Tan and Wang 2013; Fang et al. 2016). In areas with shallow groundwater levels, or in deep excavation pits, construction dewatering is widely used for lowering the water-table inside the excavation pit (Powers et al. 2007; Cashman and Preene 2013; Pujades et al. 2014). In general, dewatering procedures affect the design, the construction procedures, and overall costs of the construction project.
* J. H. van Lopik [email protected] 1
Department of Earth Sciences, Utrecht University, Princetonlaan 8, 3584, CB Utrecht, The Netherlands
2
KWR Water Cycle Research Institute, Groningenhaven 7, 3433, PE Nieuwegein, The Netherlands
Hence, dewatering systems should be carefully designed using the knowledge of the soil characteristics, hydraulic properties and construction dimensions for a specific field site (Galeati and Gambolati 1988; Wang et al.
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